Your Lovable app is shipping. The welcome emails are wired up, the password resets work, and your test inbox looks great. Then the open rates come in. They’re not great. You check your spam folder from a Gmail account you don’t normally use, and there it is. Your welcome email. Sitting in spam, between the vitamin offers and the watch ads.

This happens to almost every Lovable app that sends real email at marketing-relevant volumes. It happens for three specific reasons, and one of them is the email provider Lovable recommended when you set up the project.

Why your Lovable app’s emails are landing in spam

When you ask Lovable to “add email” to your app, it reaches for Resend. Resend is a fine product. It’s also the default in Lovable’s templates and the API the AI knows best, so that’s what gets wired in.

That’s fine for an MVP. It stops being fine when you’re trying to do marketing things at marketing volumes.

Here’s why your Lovable + Resend setup ends up in spam:

The default sender setup isn’t ready for marketing volume

Out of the box, your emails go out from a shared sending IP, on a domain you haven’t authenticated, with a from-address that looks generic. Gmail and Outlook see all of that and quietly route most of it to spam, especially when you’re sending to addresses that have never replied to you. This isn’t a Resend-specific problem. It’s a “you haven’t set up DKIM, SPF, DMARC and a custom sending domain” problem. AI builders almost never do that for you.

Your sender reputation has nowhere to grow

Sender reputation is the score Gmail, Outlook and the rest assign to the IP and domain you send from. It builds with consistent sending, low complaint rates and engaged recipients. On a shared IP, you inherit everyone else’s reputation. That can be fine. It can also be terrible.

The combination is what tanks deliverability. Not any one factor, but the stack of them.

What SendPro does that the Lovable default doesn’t

Spotler SendPro is built for transactional and marketing email at the layer where deliverability actually gets won or lost. The differences from a default Lovable + Resend setup:

Custom sending domains by default. You set up a sending subdomain (something like mail.yourapp.com), authenticate it with DKIM, SPF and DMARC, and SendPro walks you through the DNS records. Your emails go out from your own domain, with your own sender reputation. This is the single biggest deliverability lever in email, and it’s the one the AI-builder defaults almost never set up for you.

Dedicated sending pools. As your Lovable app scales, SendPro lets you move your sending onto dedicated infrastructure, so your reputation depends on how you send and not on the shared pool’s worst-behaved tenant.

Postmaster tooling. Bounce categorisation, complaint feedback loops, engagement tracking, suppression list management. The unsexy plumbing that decides whether your next campaign lands in inbox or in promotions or in spam.

EU-hosted infrastructure. If your users are in Europe, your emails go out from European infrastructure, which European inbox providers handle more efficiently. (If EU data residency matters to your customers or your compliance posture, this matters even more, and we’ve got a separate post on EU residency in Lovable apps that goes deeper.)

The result is simple. More of your Lovable app’s emails reach the inbox, and the ones that reach the inbox actually get opened.

How to swap Resend for SendPro in your Lovable app

This is the part that sounds harder than it is. About fifteen minutes total.

Step 1. Sign up for SendPro and grab five values from the dashboard:

  • Client ID
  • Client secret
  • Account ID
  • A verified sender email address
  • A sender display name

Step 2. Open your Lovable project and paste this prompt:

Replace the email sending in this project with Spotler SendPro using OAuth2 client_credentials. Auth endpoint: https://login.flowmailer.net/oauth/token. Send endpoint: https://api.flowmailer.net/{account_id}/messages/submit. Cache the access token in memory based on expires_in and retry once on 401. Use environment variables for the five SendPro credentials.

Lovable will refactor the email layer in place. The AI tends to do this swap cleanly because the SendPro API is well-documented and the OAuth2 flow is a familiar pattern.

Step 3. Add the five values to your Lovable project’s environment variables panel.

Step 4. Set up your custom sending domain. SendPro gives you the DKIM, SPF and DMARC records to add to your DNS. This is the step that does the heaviest lifting on deliverability, so don’t skip it. If you don’t have access to your domain’s DNS, ask whoever manages your website. It takes about ten minutes once the records are in front of them.

Step 5. Send a test email to a Gmail account, an Outlook account, and any other inbox your audience actually uses. Confirm it lands in the inbox (not promotions, not spam). Click through any links. Check the from address looks right.

That’s the whole swap.

A Lovable email deliverability checklist

If you’re sending any meaningful volume of email from a Lovable app, walk through these:

  1. Custom sending domain. Not your-app.resend.com. A subdomain of the domain your users recognise.
  2. DKIM, SPF, DMARC. All three set up correctly in your DNS. SendPro’s dashboard walks you through it.
  3. Consistent sender address. Don’t switch from welcome@ to noreply@ to team@ across different flows. Pick one and stick with it.
  4. Real reply-to. A noreply@ address that bounces every reply tells inbox providers you don’t want a relationship. Use a monitored reply-to.
  5. Suppression list hygiene. Honour unsubscribes. Don’t keep sending to addresses that have already bounced.
  6. Engagement signal. Send to recipients who actually open your emails. Inactive lists drag your reputation down faster than almost anything else.
  7. Test from multiple inboxes. Gmail, Outlook, Yahoo, plus whatever your users actually use day to day.

This is the unglamorous part of email marketing. It’s also the part that decides whether the campaign you spent two days designing ever gets read.

The summary, in a sentence

A Lovable app shipped with Resend will send emails, but a Lovable app shipped with Spotler SendPro gets them into inboxes, which is the version of “sending email” that actually moves the metrics you care about.

If you want to go deeper, the SendPro product overview covers the deliverability story in more detail, and the SendPro API documentation has the full reference for the OAuth2 integration Lovable will work from.